Devices for throwing plate type targets wherein the throwing or catapult arm is mechanically driven are well known in the art. In such devices the drive means, which actually imparts momentum to the throwing arm, is typically a powerful traction spring. The prior art devices thus generally comprise a throwing arm, designed to accommodate a frangible target plate, mounted on one end of a rotatable shaft. The other end of the rotatable shaft is mechanically coupled to a mechanism, which is connected to the traction spring. In operation the throwing arm is moved to an angular position in which the spring is stretched and the arm is thereafter released for the throwing stroke.
Various techniques and devices have been proposed to accomplish, against the force of the traction spring, the cocking of the throwing arm. By way of example, use has been made of crank mechanisms, wherein the throwing arm and the crank mechanism are affixed to a pivotal shaft. A traction spring is attached to the crank mechanism, which is driven by an electric motor.
The prior art devices have been characterized by a relatively complicated design, including unidirectional clamping means.